This invention relates to an improved valve mechanism for an internal combustion engine of the piston and cylinder type.
Specifically to an improved rotary valve mechanism employed to control the intake of the air/fuel mixture into the combustion chamber and also exhaust gases out of the combustion chamber.
Prior art pertaining to this subject all cites the well-known advantages of rotary valve mechanisms as compared to poppet valve designs. However to date all previous patents were concerned with sealing the intake and exhaust ports from the combustion chamber or varying the valve timing to gain combustion efficiency and emission control.
Prior designs have obscured the primary benefit of the rotary valve system. The rotary valve system presented here embodies the essential requirements of a rotary valve system. That is it eliminates as many complicated moving parts as possible and can be mass-produced in an economic manner.
The embodiment presented here has very high air/fuel flow characteristics due to the large unobstructed four valve ports per cylinder and essentially has only two moving rotary valve shafts, one intake and one exhaust featuring a variable timing mechanism.
The rotary valve system presented herein is used in an internal combustion engine of the piston and cylinder type that has a cylinder encasement such that a block and horizontally split cylinder head would be formed with a plurality of cylinders.
There are two rotary valve shafts which are encased in the horizontally split head, one shaft for the intake ports and one shaft for the exhaust ports. Each shaft contains two transverse bores for each engine cylinder. When the intake rotary valve shaft is rotated the ports formed by these bores become aligned with their respective intake passages from the cylinder head into the combustion chamber. This allows the air/fuel mixture to pass into the combustion chamber. When the intake rotary valve rotates such that these transverse ports are perpendicular to the intake passage from the head to the combustion chamber the chamber sealed by the solid portion of rotary valve shaft on its respective combustion chambers seals. Similarly when the exhaust rotary valve rotates such that its exhaust ports are aligned with its corresponding exhaust ports in the cylinder head and the combustion chamber it allows exhaust gases to exit from the combustion chamber. Likewise, when exhaust rotary valve rotates such that its ports are perpendicular to the exhaust ports in the combustion chamber the chamber is sealed.
The timing of intake rotary valve shaft and the exhaust rotary on shaft is synchronized with the engine crankshaft by means of a cog belt or timing chain. Further the timing of the intake and exhaust rotary valve shafts are individually variable through the action of individual hydraulic servomotors under the control of a computerized engine management system. This allows for each rotary valve shaft to be advanced or retarded relative to the crankshaft position under the control of the computer driven servomotors.
The unobstructed path of the four ports for each cylinder and their large diameters allows for very high airflow quantities in and out of the combustion chambers. Further the contoured shape of the rotary valve shafts allow for the combustion chamber head and to be a very efficient hemispherical configuration.